1. Field of the Invention
The present invention concerns a process for treating a molten metal during a casting operation into a mold using a filter, the process including the step, prior to casting the molten metal, of placing a material for treating said metal at a point on the channel adapted to guide said metal to the filter.
The invention also concerns a filter for implementing the process in accordance with the invention.
2. Description of the Prior Art
The treatment agents are usually merely placed in the channels for the molten metal, which is time-consuming.
It is also known to distribute products for treating the metal by placing the treatment products in destructible sachets which are disposed in a corner or a cul-de-sac of the channels for the metal upstream of the filter; this process has the drawback that it does not guarantee that all of the metal comes into contact with the treatment agents.
Because of turbulence caused by the flow of the metal in the casting channels the destructible sachets are sometimes dislodged from where they are placed and travel upstream into the funnel into which the molten metal is poured. This results in wastage of the unused treatment material and rejection of the cast parts because the metal is insufficiently treated. Also the molten metal does not enter fully into contact with the treatment material and the metal cast in the mold may not be homogeneous.
It is also known to treat the liquid metal by placing on the upstream side of the filter pastilles of treatment products held together by a binder or by pressing and/or sintering and/or molding them: once again, there is no guarantee that all of the metal has been treated. Also, this represents a further handling operation.
An object of the present invention is to remedy the drawbacks of the prior art processes and to propose a process of the aforementioned type whereby all of the cast molten metal is treated as regularly and as homogeneously as possible and the treatment material is entirely used to treat said metal.
Another object of the invention is to propose a filter for implementing said process.